Gpz1100B2 Rev counter

[scott]

Just managed to get the bike started and seems to run fine. I noticed that the rev counter worked fine for a few minutes. At some point i noticed that it dropped to zero and then at some point it went to 12 000 rpm and stayed there. It seems to have settled at 8 000 rpm now. With the engine turned off but ignition on i can test the battery voltage display on the rev counter by pressing the test button and it moves from 8000 rpm to 12 000 rpm. When i release the button it returns to 8000 rpm. What's wrong, is it the damping in the meter? Or, is it as i suspect, that the electronics have failed. I can appreciate that the electrolytic capacitors fitted are 4o year old and probably very borderline now. Any suggestions would help.

[zed1015]

Tacho wiring is just 3 wires.
+ from ignition, feed from coil and earth.
For it to constantly read a fixed rpm the fault is in the clock.
Most likely a short in the battery voltage circuit or its button and the reading you are getting is voltage even without the volt button being pressed.

[scott]

Thanks Rob, potentially one of those caps have gone short circuit then. I’ll do some checking. I have a spare Rev counter. Maybe I will just fit that one and see how it performs. How do I remove the Rev counter from the plastic body? Do I need to remove the needle/indicator first? And then clock face. If so, how do I remove it without damaging anything?

[Philippe]

Hi scott

remove the black plastic backing plate (3 screws) from the cockpit. You'll see 4 nuts, remove those, now you can remove the "cockpit" from the iron plate that attaches it to the upper triple tree. Once you have that removed, you'll see 4 other srews that fix the white plastic body to the black plastic upper shell. Remove those 4 screws and you'll be able to remove the whole white inside body with the meters attached to it. The speedometer and the rev counter are secured to it with 2 screws. If you undo those, you can remove the meters from the white plastic body. It's a lot of screw removing but you can take it apart completely.
Good luck!
GrtZ
Philippe

[scott]

Thanks Phillipe,
My spare clocks are stripped down as far as you have mentioned except for the final two screws that you have mentioned…….I’ll try to find out where those two screws are tonight….hopefully.

[scott]

Well, I replaced the Rev counter. Will test it out tomorrow but the needle feels right and the battery voltage test appears ok. The failed one’s needle flops about